A significant number of surgical patients who are diagnosed with a torn rotator cuff typically present in the operating room with a cuff that is only partially torn on the articular side of the tendon. Rather than being avulsed from the bone in a way that allows the surgeon to access the torn edge for suture placement and eventual re-attachment to the bone, these partial tears are characterized by torn tendon fibers on the articular side of the tendon and intact tendon fibers on the bursal side of the tendon. These tears have been given the label of PASTA tears (Partial Articular Supraspinatus Tendon Avulsion).
The surgeon typically assesses a rotator cuff tear by placing an arthroscope in the joint capsule and visualizing both the articular and bursal side of the tendon. The footprint of the supraspinatus tendon (one of the four tendons that comprise the rotator cuff and the most common tendon to tear) on the humeral head is typically about 1 cm in length medial to lateral and 2 to 3 cm in width anterior to posterior. When the surgeon visualizes a tear on the articular side that is not reflected entirely through the tendon footprint to the bursal side, the surgeon typically estimates the depth of the tear. If the tear is less than 5 mm (or less than roughly 50% of the tendon thickness), the typical approach is to debride the underside of the tendon while leaving the rest of the tendon alone.
If the surgeon determines that the avulsion is greater than 50% of the tendon, there are usually two possible approaches to the repair. The first approach is to complete the tear by cutting the tendon off from the bone to create a complete tear of the tendon and to proceed with a conventional arthroscopic rotator cuff repair. The second approach is to repair the tendon by inserting anchors trans-tendon into the underlying bone, passing sutures through the tendon, and then tying the tendon down.
The first approach may be a technically easier procedure to perform and many surgeons may feel that they can create a better ultimate repair by using this technique. However, this approach requires a surgeon to cut away viable tendon in order to subsequently repair it. The second approach of inserting anchors trans-tendon may be considered a more reasonable approach. However, this approach is difficult and requires a very high level of surgical skill to accomplish. Moreover, this approach also raises concerns about the size of the holes created in the tendon to place screw-type bone anchors (typically 3 to 5 mm in diameter) through the tendon and whether these holes may compromise the repair.